THE FIRST MIDINFRARED DETECTION OF A SOURCE COINCIDENT WITH SAGITTARIUS-A

We present the first mid-infrared detection of a source coincident wit h the black hole candidate Sgr A in a deep image of the inner parsec of the Galaxy. These data were obtained with SpectroCam-10 at the 200 inch (5.08 m) Hale telescope. The source was detected at 8.7 mu m on t wo separate occasions using different observing techniques. The spatia l resolution is similar to 0.7 '' and the noise level is 1.6 mJy beam( -1) in the combined mosaic near Sgr A. A source at Sgr A* is weakly a pparent in the raw data but is difficult to identify due to strong dif fuse dust emission with a mean flux density of 500 mJy arcsec(-2). Sev eral deconvolution techniques were applied to achieve the diffraction limit of 0.44 '', all of which revealed a peak on a narrow NW-SE ridge of emission. The peak is coincident with Sgr A within the +/-0.3 '' uncertainty in locating Sgr A relative to IRS 7. We estimate the flux density of the Sgr A source above the ridge to be 25 +/- 5 mJy. The extinction-corrected 8.7 mu m flux density of similar to 100 mJy is si gnificantly greater than what is predicted by dustless accretion disk models. The excess emission is best explained by warm dust which may b e associated with Sgr A or heated by local stellar sources.